Abnormal cardiac morphology, function and energy metabolism in the dystrophic mdx mouse: an MRI and MRS study.
Patients with muscular dystrophy have abnormal cardiac function and decreased high-energy phosphate metabolism. Here, we have determined whether the 8 month old mdx mouse, an animal model of muscular dystrophy, also has abnormal cardiac function and energetics. In vivo cardiac MRI revealed 33% and 104% larger right ventricular end-diastolic and end-systolic volumes, respectively, and 17% lower right ventricular ejection fractions in mdx mice compared with controls. Evidence of left ventricular diastolic dysfunction included 18% lower peak filling rates in mdx mouse hearts. Abnormal cardiac function was accompanied by necrosis and lower citrate synthase activity in the mdx mouse heart, suggesting decreased mitochondrial content. Decreased mitochondrial numbers were associated with 38% lower phosphocreatine concentration, 22% lower total creatine, 36% higher cytosolic free ADP concentration and 1.3 kJ/mol lower free-energy available from ATP hydrolysis in whole isolated, perfused mdx mouse hearts than in controls. Transsarcolemmal creatine uptake was 12% lower in mdx mouse hearts. We conclude that the absence of dystrophin in adult mdx mouse heart, as in the heart of human patient, is associated with right ventricular dilatation, left ventricular diastolic dysfunction and abnormal energy metabolism.
Zhang
Wen
W
Department of Physiology, Anatomy and Genetics, Sherrington Building, University of Oxford, Oxford, UK.
ten Hove
Michiel
M
Schneider
Jürgen E
JE
Stuckey
Daniel J
DJ
Sebag-Montefiore
Liam
L
Bia
Britta L
BL
Radda
George K
GK
Davies
Kay E
KE
Neubauer
Stefan
S
Clarke
Kieran
K
D000244:Adenosine Diphosphate / Q000378:metabolism; D000255:Adenosine Triphosphate / Q000378:metabolism; D000818:Animals; D002950:Citrate (si)-Synthase / Q000378:metabolism; D004734:Energy Metabolism; D006868:Hydrolysis; D008279:Magnetic Resonance Imaging; D008297:Male; D051379:Mice; D018101:Mice, Inbred mdx; D008929:Mitochondria, Heart / Q000378:metabolism / Q000473:pathology; D009136:Muscular Dystrophies / Q000378:metabolism* / Q000473:pathology* / Q000503:physiopathology; D009137:Muscular Dystrophy, Animal / Q000378:metabolism* / Q000473:pathology* / Q000503:physiopathology; D009206:Myocardium / Q000378:metabolism* / Q000473:pathology*; D009336:Necrosis; D010725:Phosphocreatine / Q000378:metabolism; D012508:Sarcolemma / Q000378:metabolism / Q000473:pathology; D013318:Stroke Volume
D010725:Phosphocreatine; D000244:Adenosine Diphosphate; D000255:Adenosine Triphosphate; D002950:Citrate (si)-Synthase